CORONARY ARTERIAL FISTULAS

CORONARY ARTERIAL FISTULAS. These anomalies represent one of the most common major congenital malformations of the coronary circulation that permit adult survival.70 Both coronary arteries arise from the aorta at their normal sites, but a fistulous branch of one or more arteries communicates directly with a cardiac chamber or with the pulmonary trunk, coronary sinus, vena cava, or a pulmonary vein. Clinically occult coronary arterial fistulas, generally to the pulmonary artery, have been found in a small but consistent percentage of adults undergoing diagnostic coronary angiography for other reasons.71 Survival into adulthood is the rule, although life span is not normal.70 Longevity depends upon the amount of blood traversing the communication, the chamber or vessel into which the fistula drains, and the presence and degree of myocardial ischemia that might result when the fistula causes a coronary steal.72 Occasional survivals have been recorded in the seventh and eighth decades, with one report of a patient living to age 84.73 Death, when it comes, may be due to noncardiac causes or to acquired coronary artery disease.

CONGENITAL PULMONARY ARTERIOVENOUS FISTULA

CONGENITAL PULMONARY ARTERIOVENOUS FISTULA. These fistulas can be solitary or multiple, unilateral or bilateral, or minute and diffuse throughout both lungs, and are usually associated with hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome).74 A substantial majority go unrecognized until adulthood.5 Dyspnea and fatigue are often related to anemia caused by bleeding telangiectases rather than to the pulmonary arteriovenous fistulas per se. Two of the author’s patients without telangiectasia were siblings aged 71 and 73 years (Fig. 30–8 Fig. 30–8 ).75

Common Defects in Which Unoperated Adult Survival is Exceptional

Common Defects in Which Unoperated Adult Survival is Exceptional

VENTRICULAR SEPTAL DEFECT

VENTRICULAR SEPTAL DEFECT (see also [For More Information] , Fig. 29–16 Fig. 29–16 ). These defects are among the most common congenital cardiac malformations at birth but are seldom found in adulthood.76,77 Adult survivors comprise two widely disparate groups78–80: (1) those with defects that have either closed spontaneously or decreased to a small or moderately restrictive size, and (2) those with nonrestrictive defects with elevated pulmonary vascular resistance that relieves the left ventricle of volume overload while imposing no additional afterload upon the systemic right ventricle (Eisenmenger’s complex).

The chief reason for adult survival in patients with ventricular septal defects is spontaneous closure.81 Paul Wood asked, “Where’s the maladie de Roger? Assuming it does not provide immortality, it must either close spontaneously in middle life or have long since run its mortal course.”82 Early spontaneous closure by formation of septal aneurysm leaves the patient with a functionally normal heart that still harbors a morphological abnormality.83 The occasional adult survivor with persistent patency of a small perimembranous ventricular septal defect confronts a cumulative risk of infective endocarditis.84

It is the rule rather than the exception for patients with Eisenmenger’s complex to reach adulthood. The author’s oldest patient died from noncardiac causes at age 69 years.

FALLOT’S TETRALOGY

FALLOT’S TETRALOGY (see also [For More Information] ). Arthur Fallot recognized that “. . . cyanosis, especially in the adult, is the result of a small number of cardiac malformations. . . . One of these cardiac malformations is much more frequent than others . . .”6 namely, the tetralogy to which he referred. Fallot’s tetralogy represents the largest proportion of adults with cyanotic congenital heart disease, but only 6 per cent of unoperated patients are alive at age 30 and 3 per cent at age 40.85,86 There are individual reports of survival into the seventh decade.85 Fallot’s tetralogy with pulmonary atresia and adequate but not excessive aortic-to-pulmonary collateral circulation occasionally permits survival not only to adolescence but to adulthood.87 One of the author’s patients lived to age 55, despite acquired calcific aortic stenosis.

Systemic hypertension is a special problem in adult survivors, because the increase in afterload is imposed on both the left and right ventricles (biventricular aorta).5 The rise in right ventricular systolic pressure may augment pulmonary blood flow and reduce cyanosis but at the price of right ventricular (or biventricular) failure. Infective endocarditis on an incompetent biventricular aortic valve may incur catastrophic acute severe aortic regurgitation into both right and left ventricles.

Late Survival After Cardiac Surgery or Interventional Catheterization

Late Survival After Cardiac Surgery or Interventional Catheterization

An understanding of long-term outcomes requires knowledge of the preoperative or preinterventional congenital malformation, the nature and effects of the therapeutic intervention, and the subsequent residua and sequelae.2 Success is measured not only by the length of survival but also by the quality of life and the need for reoperation. Surgical refinements affect long-term outcome, often significantly. Techniques have evolved and will continue to do so. Patients who underwent cardiac surgery decades ago benefited from the anatomical repairs but often suffered from deleterious effects of inadequate intraoperative myocardial protection.2 Prosthetic materials—valves, patches, conduits—that were previously state of the art have been superseded by many generations of improved devices and materials.

Congenitally Malformed Cardiac Valves

Congenitally Malformed Cardiac Valves

ISOLATED PULMONARY VALVE STENOSIS

ISOLATED PULMONARY VALVE STENOSIS (see also [For More Information] and 924). Balloon dilatation has largely replaced surgery for typical isolated congenital pulmonary valve stenosis, provided that the stenotic valve is thin, pliant, and mobile (Fig. 30–9 Fig. 30–9 ).88,89 Secondary hypertrophic subpulmonary stenosis tends to regress after successful dilatation of the stenotic valve (Fig. 30–4 Fig. 30–4 ). Long-term results of balloon valvuloplasty have thus far been as good as those of surgical valvotomy.87 If pulmonary stenosis is relieved during childhood, long-term survival patterns are similar to those in age- and sex-matched controls.87 Exemplary results are qualified by age at intervention and by the severity of the stenosis before relief. The more severe and protracted the obstruction, the less optimal the long-term outcome, including late death from right ventricular failure. These conclusions support the practice of relieving hemodynamically significant pulmonary valve stenosis during childhood but underscore the desirability of surveillance through adolescence and adulthood. With few exceptions, postinterventional or postoperative pulmonary regurgitation is no more than mild to moderate. Residual dilatation of the pulmonary trunk is of no clinical significance even when marked. Susceptibility to infective endocarditis is believed to be low if not absent if the postinterventional gradient is small and if pulmonary regurgitation is absent or mild.

CONGENITAL AORTIC VALVE STENOSIS

CONGENITAL AORTIC VALVE STENOSIS (see also [For More Information] and 914). Balloon dilatation in young patients with congenital bicuspid aortic stenosis is feasible provided the valve is thin and mobile, with no calcific deposits (Fig. 30–10A Fig. 30–10A ). The best that can be achieved, however, is separation of the fused commissures that results in a functionally normal bicuspid aortic valve (Fig. 30–10B Fig. 30–10B ) with an outlook analogous to that of surgical reconstruction.90,91 The repaired valve has at least the same tendency as an unoperated, functionally normal bicuspid aortic valve to develop regurgitation or to thicken, calcify, and become stenotic with the passage of time (Fig. 30–1 Fig. 30–1 ). The risk of infective endocarditis is not affected by either balloon dilatation or surgical reconstruction. The enhanced ejection performance of the left ventricle in young patients with congenital aortic stenosis92 tends to be maintained after relief of the obstruction, provided relief is achieved before contractility begins to decline.92,93 If the aortic valve is replaced, the fate of the prosthesis and the need for anticoagulants are important determinants of late postoperative outcome. The inherent risk of aortic root dissection (Fig. 30–2 Fig. 30–2 ) persists after either balloon dilatation, direct reconstruction, or aortic valve replacement.

A functionally normal bicuspid aortic valve may develop gradually progressive aortic regurgitation that requires surgical relief using a prosthetic valve. Prime objectives of valve replacement are removal of left ventricular volume overload and preservation or restoration of satisfactory left ventricular systolic function. Even if these objectives are achieved, a minority of patients die late after operation, not because of heart failure but because of what is presumed to be a disturbance in ventricular rhythm (sudden death). Infective endocarditis can convert a bicuspid aortic valve that is functionally normal into the catastrophic hemodynamic fault of acute severe aortic regurgitation that, with few exceptions, requires emergency valve replacement.15

EBSTEIN’S ANOMALY

EBSTEIN’S ANOMALY (see also [For More Information] and 966). This malformation is the most common cause of surgically important congenital tricuspid regurgitation.94 The timing and success of operation in large part depend on whether or not the malformed valve can be reconstructed rather than replaced. Transesophageal echocardiography provides a secure basis for judging whether a large mobile anterior tricuspid leaflet can be used to create a competent unicuspid valve. Successful operation relieves right ventricular volume overload, improves right ventricular function, removes the risk of paradoxical emboli through an interatrial communication, and interrupts right atrioventricular bypass tracts, eliminating the hazard of rapid ventricular response to atrial flutter or fibrillation (Fig. 30–7 Fig. 30–7 ). Supraventricular arrhythmias may recur postoperatively, but if the accessory pathways have been divided, the ventricular response is not accelerated, and the arrhythmias are more likely to respond to pharmacological management. Tissue valves are used for tricuspid replacement because mechanical prostheses function poorly in the tricuspid location in addition to posing the risk of pulmonary embolization even with anticoagulation.

ISOLATED INCOMPETENCE OF THE LEFT-SIDED ATRIOVENTRICULAR VALVE IN CONGENITALLY CORRECTED TRANSPOSITION OF THE GREAT ARTERIES

ISOLATED INCOMPETENCE OF THE LEFT-SIDED ATRIOVENTRICULAR VALVE IN CONGENITALLY CORRECTED TRANSPOSITION OF THE GREAT ARTERIES. The Ebstein-like anomaly that causes incompetence of the tricuspid valve in the systemic (inverted) position is analogous to, but not identical to, Ebstein’s anomaly as just described.5 The anterior leaflet is smaller in size than in right-sided Ebstein’s anomaly and is usually malformed. Accordingly, when surgical relief of regurgitation is indicated, the left-sided tricuspid valve almost always requires replacement. Long-term outcome is then determined by the duration of preoperative regurgitation, the functional adequacy (or inadequacy) of a morphological right ventricle in the systemic location, and an accrued incidence of high-degree atrioventricular heart block.

ATRIAL SEPTAL DEFECT (OSTIUM SECUNDUM)

ATRIAL SEPTAL DEFECT (OSTIUM SECUNDUM) (see also [For More Information] and 966). Children, adolescents, and young adults with this malformation usually have few or no symptoms.5 An assessment of asymptomatic or minimally symptomatic patients with ostium secundum or sinus venosus atrial septal defects who were over 25 at the time of presentation disclosed no difference in survival or symptoms and no difference in the incidence of new arrhythmias, stroke, embolic phenomena, or cardiac failure between medically and surgically managed patients after a mean follow-up of 25 years.95 The study confirmed that progressive pulmonary vascular disease does not develop in this patient population, so its anticipation is not a rationale for operation.95,96 Long-term observations after closure of atrial septal defects found that actuarial 27-year rates of survival in patients 12 to 24 years of age at operation were the same as for normal patients; operation at 25 to 41 years of age was followed by long-term survival that was good but not normal, whereas closure after age 41 years was associated with a significant increase in late mortality and in the frequency of late cardiac failure, stroke, and atrial fibrillation.97 The age beyond which surgery should not be offered has been questioned.95,98 However, in patients older than age 40 years, a recent multivariate analysis of 84 postoperative patients with atrial septal defects was compared with results in 95 patients who had been treated medically; there was a significant reduction in overall mortality and considerable improvement in long-term functional status of the surgically treated patients.99 Long-term functional improvement was sustained in 69 per cent of patients who had suffered from severe heart failure before surgery.99 In contrast to the clear benefit of surgery with respect to long-term survival and symptomatic improvement, repair later in life did not significantly reduce the prevalence of atrial fibrillation or flutter or morbidity associated with thromboembolic complications.99

COMPLETE TRANSPOSITION OF THE GREAT ARTERIES

COMPLETE TRANSPOSITION OF THE GREAT ARTERIES (see also [For More Information] ). A relatively large number of patients with this malformation have reached adulthood because of a Rashkind balloon atrial septostomy as neonates followed by intraatrial redirection of venous return (Mustard or Senning atrial switch operations).2 Twenty-year survival after atrial switch has been reported at 80 to 90 per cent, but major late postoperative sequelae are the rule.100,101 Intraatrial repair involves excision of the atrial septum and insertion of a pericardial or Dacron baffle that directs systemic venous return across the mitral valve into the left ventricle and pulmonary artery and that directs pulmonary venous return across the tricuspid valve into the right ventricle and aorta.102 Electrophysiological sequelae of this extensive reconstruction are damage to the sinus node, atrial arrhythmias (atrial fibrillation or flutter), and damage to the atrioventricular node (Fig. 30–11 Fig. 30–11 ).103,104 During long-term follow-up, 2 to 8 per cent of patients die suddenly due to bradyarrhythmias, atrial tachyarrhythmias, or high-degree atrioventricular block. A second major postoperative concern is the long-term performance of a morphological right ventricle in the systemic location.105,106 Progressive systolic dysfunction is not uncommon, and there is a relatively high incidence of coexisting left ventricular dysfunction.106,107 Aortic regurgitation, still another late postoperative concern, exerts a negative impact on already depressed function of the morphological right ventricle.

FALLOT’S TETRALOGY

FALLOT’S TETRALOGY (see also [For More Information] ). Assessment of the postoperative course must take into account the morphological variations of the basic malformation, previous shunt procedures, age at intracardiac repair, and the presence and degree of postoperative residua and sequelae.108,110 Patients who had undergone palliative shunts, followed by intracardiac repair in early childhood, experienced 87 per cent survival 10 to 20 years after operation.109 All but a minority were free from significant cardiac or vascular symptoms and were leading normal lives. Some patients who reach adulthood after successful shunt operations in infancy or early childhood maintain improvement for decades and ultimately benefit from intracardiac repair as adults. The outlook for patients who had a Waterston or Potts shunt before intracardiac repair is more guarded, because these shunts lend themselves to the risk of excessive pulmonary blood flow, pulmonary vascular disease, or kinking of a pulmonary artery.109 A technically good intracardiac repair in infancy substantially improves cumulative survival, reduces incidence of complications, and improves quality of life.109,110 Older age at the time of intraventricular repair was a powerful predictor of poor late survival.109,111,112

The effectiveness of surgery must take into account not only survival but symptomatic status, postoperative residua and sequelae, and the need for reoperation.113 Late postoperative sudden death has been a legitimate concern. Ventricular electrical instability, rather than high-degree heart block, is now considered the major risk factor.108,109,109a Ventricular ectopic rhythms correlate with older age at intracardiac repair, with postoperative right ventricular pressure or volume overload, and with depressed right ventricular function.108,109 Postoperative left ventricular dysfunction is related to age at the time of intracardiac repair and to previous shunt procedures. A decrease in left ventricular volume and ejection fraction is a feature of severe cyanotic Fallot’s tetralogy because of reduced pulmonary arterial blood flow (underloading).114 A shunt operation increases left ventricular volume, sometimes excessively, setting the stage for late postoperative electrical instability. If primary intracardiac repair is undertaken after 2 years of age, left heart volumes approach normal, but left ventricular function may remain subnormal.114,115

The emphasis on disturbances in ventricular rhythm after intracardiac repair of Fallot’s tetralogy should not obscure the importance of disturbances in atrial rhythm.116 Atrial fibrillation, atrial flutter, and supraventricular tachycardia were important determinants of morbidity in approximately one-third of patients. Attention was also called to the incidence of sinus node dysfunction, with pacemakers needed twice as often for sinus bradycardia as for atrioventricular block.116

PATENT DUCTUS ARTERIOSUS

PATENT DUCTUS ARTERIOSUS (see also [For More Information] ). Division of an isolated restrictive patent ductus arteriosus in childhood represents one of the few literal cures of congenital malformations of the heart and circulation. Transcatheter ductal occlusion must compete with this record, which is ideal except for the thoracotomy.117 The risk of infective endocarditis is eliminated. When a ductus is moderately restrictive or nonrestrictive, division in early childhood usually results in regression of left atrial and left ventricular enlargement and normalization of pulmonary arterial and right ventricular systolic pressures. Adult survival of patients with a nonrestrictive patent ductus depends on a rise in pulmonary vascular resistance that relieves the left ventricle of volume overload but incurs inoperability when the shunt is reversed.

COARCTATION OF THE AORTA

COARCTATION OF THE AORTA (see also [For More Information] ). Repair in early childhood results in 89 per cent survival at 15 years and 83 per cent at 25 years.118 Postoperative residua and sequelae are common, however, and require long-term follow-up.119,120 Three principal postoperative concerns include residual systolic hypertension despite absence of a coarctation gradient, bicuspid aortic valve, and recoarctation. A major risk factor for persistent postoperative hypertension is older age at repair: i.e., the duration of preoperative hypertension that results in baroreceptor abnormalities and compliance changes in the walls of the major arteries.121,122

The fate of a coexisting functionally normal bicuspid aortic valve is the same as that of an isolated congenitally bicuspid aortic valve as described earlier. Recurrence of coarctation after reparative surgery is related chiefly to the technique used for the initial repair.123 Resection with end-to-end anastomosis, when technically feasible, is associated with the lowest incidence of recoarctation. Balloon dilatation has been a step forward in the management of recoarctation, but not of the native obstruction.124 The histology of the aorta immediately distal to the coarctation resembles that of the Marfan syndrome. Balloon dilatation further injures this inherently vulnerable segment.20 Conversely, resection with end-to-end anastomosis removes the vulnerable segment, an advantage to women during subsequent pregnancy. Premature coronary artery atherosclerosis, myocardial infarction, and congestive heart failure were causes of death in 12 per cent of patients 11 to 25 years after coarctectomy.119 Early successful repair promises to minimize these late complications. Congenital aneurysms of the circle of Willis (Fig. 30–3 Fig. 30–3 ) are uncommon but well-established coexisting malformations in patients with coarctation of the aorta and set the stage for catastrophic cerebral hemorrhage. Rupture of an aneurysm has been reported in normotensive patients long after successful coarctation repair.125 Abnormalities of the mitral apparatus occur in 26 to 58 per cent of patients with coarctation and vary from clinically occult and functionally benign to overt stenosis or incompetence of the mitral orifice.126

CONGENITAL SINUS OF VALSALVA ANEURYSMS

CONGENITAL SINUS OF VALSALVA ANEURYSMS (see also [For More Information] ). An acute large rupture announces itself dramatically, whereas as a small perforation that develops gradually or an unruptured aneurysm may go unnoticed, at least initially.5 In any event, surgical mortality is low, and late results of repair are excellent, especially when aortic valve regurgitation is absent.

THE FONTAN PROCEDURE

THE FONTAN PROCEDURE (see Figs. 29–55 Figs. 29–55 , and 29–69 29–69 ). In 1971, Fontan and Baudet reported a new operation for tricuspid atresia (caval-to-pulmonary artery anastomosis)127 that bears the first author’s name as an eponym. The Fontan operation has emerged as a landmark in the surgical treatment of congenital heart disease.128 Complete bypass of the right ventricle was a logical extension of its predecessor, the partial right heart bypass procedure introduced by Glenn.129 The original Glenn shunt consisted of an anastomosis of the superior vena cava to the right pulmonary artery that was divided from the pulmonary trunk.129 Acquired right lower-lobe pulmonary arteriovenous fistulas were late postoperative complications.130 The procedure has now been modified as the “bidirectional Glenn shunt,” represented by anastomosis of the superior vena cava to an undivided right pulmonary artery.130 The bidirectional Glenn shunt is used as palliation in patients for whom a Fontan operation is not considered feasible or as the first stage in anticipation of total caval-to-pulmonary arterial connection, which is the most recent modification of the Fontan repair.130,131 and 132 and 132a Among 352 patients who had a Fontan operation prior to 1995, the 10-year survival was 60 per cent.132 Survival was adversely affected by depressed ventricular function, increased pulmonary arterial pressure, and atrioventricular valve dysfunction.132 Meticulous selection of patients increases late survival and reduces morbidity. As experience has accumulated, operative risk has declined, survival has improved, morbidity has decreased, and the quality of life has improved, sometimes appreciably.132 and 132a,133,134

The Fontan operation for patients 18 years or older has also been successful, occasionally achieving remarkable degrees of rehabilitation.133 There are, however, a number of caveats. Because of the importance of ventricular function, postoperative afterload reduction using angiotensin-converting enzyme inhibitors is common practice, and the importance of maintaining sinus rhythm has been emphasized.133,134 Atrial arrhythmias, especially atrial flutter or fibrillation, adversely affect ventricular function and may precipitate congestive heart failure. Thrombotic and thromboembolic events are additional concerns and do not appear to be related to ventricular function or disturbances in atrial rhythm.132 Thrombi have been identified in the superior vena cava, inferior vena cava, lateral tunnel, right atrium, and the ventricular chamber, setting the stage for pulmonary and systemic emboli. Anticoagulation is an important consideration.

Date: 2014-12-21; view: 899